WASHINGTON (Reuters) – China’s cooperation with Moscow since Russia’s invasion of Ukraine and Chinese comments against NATO enlargement show why the Western defense alliance should regard Beijing as a security challenge, Secretary-General Jens Stoltenberg said on Wednesday. “The sum of all is this just increases the importance of NATO allies standing together and realizing that China is part of the security challenges we need to face today and in the future,” Stoltenberg said in an interview with Reuters. Stoltenberg also noted China’s “coercive behavior” in the South China Sea and against its…